2 replies to this topic

[jonnyenglish]

Hi guys I'm not very clever but at the moment my battery doesn't seem to be charging the voltage at the battery whilst idling is 12.5v which in my thinking should be more like 14 does this mean I need to get a new alternator? If so which do I need?

Thanks

Jonny

[dklawson]

You may need an alternator but always check the simple, cheap, and quick things first.  For example... make sure the belt is tightened and that the heavy brown wires leaving the alternator are intact.  If you have a voltmeter this is easy to confirm.  Disconnect the alternator plug and use your meter to measure the voltage between the large terminals in the plug and earth.  You should find 12V on both big terminals in the plug.  If you don't find 12V on them, you have a wiring problem.  If you don't have a meter make a test lamp.  Solder two short lengths of wire to a turn signal lamp (one to the case, one to the tip).  Wrap the lamp base with electrical tape, and use the two wires between the alternator plug terminals and earth instead of a meter.  A glowing lamp indicates 12V.

 

What is the red charge warning light doing?  It is part of the circuit, not just a lamp... it must work for the alternator to charge.  The warning lamp should behave as follows.

• OFF when the key is out of the ignition.
• ON when the key is in the run position and the engine is NOT running
• OFF when the key is in the run postion and the engine IS running.

If the warning light is not on in turning on at all, try replacing the bulb.  Let us know what the warning lamp is doing relative to the three conditions above.

[jonnyenglish]

Thanks for your help mate! I did all the stuff you said about and it turned out to be the alternator so have fitted a new one and is now showing 14.5 volts at the battery. Thanks again for your help!